2. • Sample size determination is a critical aspect of designing a research
study or conducting a survey.
• The sample size refers to the number of individuals or items selected
from a population to represent it adequately and draw valid
conclusions.
• An appropriate sample size ensures that the results obtained from the
sample are generalizable to the entire population.
3. There are several factors to consider when
determining the sample size:
• Population Size: The size of the target population is a fundamental
factor in sample size determination.
Ex: 5000
• Confidence Level: The confidence level represents the level of
certainty or reliability you want to have in your results.
Ex:
90%, 95%, 99%
• margin of Error: The margin of error is the maximum allowable
difference between the sample estimate and the true population
parameter.
Ex: +/- 5%
• Degree of Variability in the Population: If there is high variability
in the population, a larger sample size is needed to capture this
diversity accurately.
Ex:
P=.5
4. Commonly used methods to calculate sample size include:
• - For estimating proportions or percentages: Formula for
sample size for proportions.
• - For estimating means or continuous variables: Formula
for sample size for means.
• - For comparing two groups (e.g., in experimental studies):
Formula for sample size for comparing two proportions or
means.
